Response of Leaf Senescence, Photosynthetic Characteristics, and Yield of Summer Maize to Controlled-Release Urea-Based Application Depth

To explore the response of summer maize leaf senescence, photosynthetic characteristics, and yield to depth one-time base application controlled-release urea, which provides a theoretical basis for light simplified production maize. Seven treatments were set up with Zhengdan 958 as material under field conditions, including no nitrogen fertilizer (CK), surface spreading (DP0), furrow 5 cm (DP5), 10 (DP10), 15 (DP15), 20 (DP20), 25 (DP25). The results showed that same rate, there are significant differences in effects senescence characteristics increase fertilization depth, DP10 DP15 have best effects. LAI increased by 5.1% 5.5% compared DP0 at tasseling stage, chlorophyll content 6.8% 7.3% days after tasseling. Compared DP0, superoxide dismutase (SOD) 13.1% 10.5%, soluble protein significantly, while malondialdehyde (MDA) decreased 9.8% 10.8%, respectively. In addition, Pn Gs ear-leaf significantly 13.9%, 16.5%, 26.1% 31.9% respectively, over Ci 22.3% 26.4%, respectively; meanwhile, photochemical quenching (qP) quantum (?PSII) reaction center photosystem II (PSII) improved, non-photochemical (NPQ) was reduced. heightened significantly; two-year average value 5.7% 6.0% DP0; kernels per spike 1000-kernels weight 4.8%, 5.2%, 4.1%, Comprehensive analysis LAI, content, various protective enzyme activities MDA, 10–15 is appropriate when rate urea 225 kg N hectare. consequence, optimizing mode could improve utilization efficiency obtain higher maize, technical support large-scale urea.